Keyswitch

Abstract

A keyswitch uses a combination of springs connected in serial for providing a return force to a keycap of the keyswitch. When the keycap moves toward a base of the keyswitch beyond a transition position, one of the springs stops continuously deforming. It leads to an increment of the elastic coefficient of the combination of springs and an increment of the elastic stored energy by the combination of springs. Therefore, during a pressing on the keycap, the keycap can provide a light force feedback and then a heavy force feedback to a user. Further, the keyswitch can use a switch with a lateral motion, which can reduce influence of a resilient force produced by the switch on the up and down movement of the keycap. The keyswitch also can use an elastic piece disposed beside the keycap, which can provide a tactile feedback to the user.

What is claimed is: 
     
       1. A keyswitch, comprising:
 a keycap; 
 a base, disposed under the keycap and comprising a boss extending toward the keycap; and 
 a combination of springs, disposed between the keycap and the base, the combination of springs comprising a first spring and a second spring connected with the first spring in series, so that when the keycap receives a pressing force to move from an initial position toward the base, the keycap transfers the pressing force to the combination of springs, and the pressing force is then transferred to the base through the first spring and the second spring in order, an outer diameter of the boss being less than a coil inner diameter of the second spring, the outer diameter of the boss being larger than a coil inner diameter of the first spring, the second spring being sleeved on the boss and comprising a plurality of elastic coils; 
 
       wherein when the keycap moves from the initial position toward the base beyond a transition position, the second spring is fully compressed to be solid such that a height of the compressed spring reaches a corresponding solid height, a lower end of the first spring abuts against the boss, the first spring is not fully compressed and remains elastically deformable as the keycap moves toward the base further, and the plurality of elastic coils substantially stack vertically. 
     
     
       2. The keyswitch of  claim 1 , further comprising a light source, wherein the boss further has a receiving hole, the receiving hole vertically extends through the boss, a horizontal cross-section of the light source is smaller than the coil inner diameter of the first spring, a vertical height of the light source is higher than the boss, and the light source passes through the receiving hole and extends upward into the combination of springs. 
     
     
       3. The keyswitch of  claim 2 , wherein the keycap further comprises a bottom receiving space, when the keycap is at the initial position, a top of the first spring is higher than a top of the light source, and when the keycap is located lower than the transition position, the top of the light source is higher than the top of the first spring, and a portion of the light source is located within the bottom receiving space. 
     
     
       4. The keyswitch of  claim 1 , further comprising a switch, wherein the switch is fixed on the base, the switch comprises a fixed contacting part and a movable contacting part disposed neighboring to the fixed contacting part, the keycap comprises a triggering portion, when the keycap is at the initial position, the triggering portion pushes against the movable contacting part to make the movable contacting part separated from the fixed contacting part, when the keycap moves toward the base beyond a triggering position, the triggering portion and the movable contacting part are separate so that the movable contacting part moves to contact the fixed contacting part, and the triggering position is located between the initial position and the transition position so that after the switch is conducted, the keycap is movable downward further to reach the transition position. 
     
     
       5. The keyswitch of  claim 4 , wherein a lower end of the second spring is disposed on the base, and an extension portion extends from the lower end of the second spring and forms the fixed contacting part. 
     
     
       6. The keyswitch of  claim 1 , further comprising a switch and an elastic piece, wherein the switch is fixed on the base, the switch comprises a fixed contacting part and a movable contacting part disposed neighboring to the fixed contacting part, the base comprises two first sliding parts disposed oppositely, the keycap has two second sliding parts, an engaging part, and a triggering portion, the two second sliding parts are positioned on opposite sides of the keycap, the engaging part and the triggering portion are positioned on opposite sides of the keycap, the first sliding parts and the two second sliding parts are slidably engaged with each other, when the keycap is at the initial position, the triggering portion pushes against the movable contacting part to make the movable contacting part separated from the fixed contacting part, the elastic piece comprises an elastic portion and a protruding portion disposed on the elastic portion, and when the keycap moves up and down relative to the base, the engaging part pushes against the protruding portion so that the elastic portion elastically deforms. 
     
     
       7. The keyswitch of  claim 6 , wherein the elastic piece comprises a sliding portion, the elastic portion is connected to the sliding portion, the base comprises an elastic piece socket, the elastic piece socket has a sliding slot, and the elastic piece is slidably disposed in the elastic piece socket by the sliding portion sliding in the sliding slot. 
     
     
       8. The keyswitch of  claim 7 , wherein when the keycap moves from the initial position toward the base to a triggering position, the engaging part obliquely downward pushes against the protruding portion to prevent the sliding portion move upward along the sliding slot. 
     
     
       9. The keyswitch of  claim 8 , wherein when the keycap proceeds to move downward from the triggering position, the engaging part obliquely upward pushes against the protruding portion, so that the sliding portion moves upward along the sliding slot. 
     
     
       10. The keyswitch of  claim 9 , wherein the sliding portion has an upper edge, the base has an accommodating space and a lower surface corresponding to the upper edge, the protruding portion is higher than the upper edge and received within the accommodating space, and the upper edge is beneath the lower surface, so that the sliding portion moves upward along the sliding slot until the upper edge engaging with the lower surface of the base. 
     
     
       11. A keyswitch, comprising:
 a keycap, comprising a triggering portion; 
 a base, disposed under the keycap; 
 a combination of springs, disposed between the keycap and the base, the combination of springs comprising a first spring and a second spring connected with the first spring in series, so that when the keycap receives a pressing force to move from an initial position toward the base, the keycap transfers the pressing force to the combination of springs, and the pressing force is then transferred to the base through the first spring and the second spring in order; and 
 a switch, fixed on the base and comprising a fixed contacting part and a movable contacting part disposed neighboring to the fixed contacting part, the movable contacting part being a cantilever structure, the cantilever structure having a fixed end, a free end, and a contacting portion, the cantilever structure being fixed on the base through the fixed end, the contacting portion being located between the fixed end and the free end and being used for electrically contacting the fixed contacting part; 
 
       wherein when the keycap moves from the initial position toward the base beyond a transition position, one of the first spring and the second spring is fully compressed to be solid such that a height of the compressed spring reaches a corresponding solid height, and the other one of the first spring and the second spring is not fully compressed and remains elastically deformable as the keycap moves toward the base further, the compressed spring whose height reaches the corresponding solid height comprises a plurality of elastic coils, and the plurality of elastic coils substantially stack vertically; 
       wherein when the keycap is at the initial position, the triggering portion pushes against the movable contacting part through the free end to make the movable contacting part separated from the fixed contacting part, and when the keycap moves toward the base beyond a triggering position, the triggering portion and the movable contacting part are separate so that the movable contacting part moves to contact the fixed contacting part through the contacting portion. 
     
     
       12. The keyswitch of  claim 11 , further comprising a light source, wherein the base comprises a boss, the boss extends toward the keycap, an outer diameter of the boss is less than a coil inner diameter of the second spring, the outer diameter of the boss is larger than a coil inner diameter of the first spring, the second spring is sleeved on the boss, when the keycap moves toward the base beyond the transition position, the second spring is compressed to be solid such that a height of the second spring reaches a corresponding solid height, and a lower end of the first spring abuts against the boss, the boss further has a receiving hole, the receiving hole vertically extends through the boss, a horizontal cross-section of the light source is smaller than the coil inner diameter of the first spring, a vertical height of the light source is higher than the boss and the light source passes through the receiving hole and extends upward into the combination of springs. 
     
     
       13. The keyswitch of  claim 12 , wherein the keycap further comprises a bottom receiving space, when the keycap is at the initial position, a top of the first spring is higher than a top of the light source, and when the keycap is located lower than the transition position, the top of the light source is higher than the top of the first spring, and a portion of the light source is located within the bottom receiving space. 
     
     
       14. The keyswitch of  claim 11 , wherein the triggering position is located between the initial position and the transition position so that after the switch is conducted, the keycap is movable downward further to reach the transition position. 
     
     
       15. The keyswitch of  claim 14 , wherein a lower end of the second spring is disposed on the base, and an extension portion extends from the lower end of the second spring and forms the fixed contacting part. 
     
     
       16. The keyswitch of  claim 11 , further comprising an elastic piece, wherein the base comprises two first sliding parts disposed oppositely, the keycap comprises an engaging part and two second sliding parts, the two second sliding parts are positioned on opposite sides of the keycap, the engaging part and the triggering portion are positioned on the opposite side of the keycap, the first sliding parts and the two second sliding parts are slidably engaged with each other, so that a movement of the keycap between the initial position and the transition position is a linear movement, the elastic piece comprises an elastic portion and a protruding portion disposed on the elastic portion, and when the keycap moves up and down relative to the base, the engaging part pushes against the protruding portion so that the elastic portion elastically deforms. 
     
     
       17. The keyswitch of  claim 16 , wherein the elastic piece comprises a sliding portion, the elastic portion is connected to the sliding portion, the base comprises an elastic piece socket, the elastic piece socket has a sliding slot, and the elastic piece is slidably disposed in the elastic piece socket by the sliding portion sliding in the sliding slot. 
     
     
       18. The keyswitch of  claim 17 , wherein when the keycap moves from the initial position toward the base to the triggering position, the engaging part obliquely downward pushes against the protruding portion to prevent the sliding portion move upward along the sliding slot. 
     
     
       19. The keyswitch of  claim 18 , wherein when the keycap proceeds to move downward from the triggering position, the engaging part obliquely upward pushes against the protruding portion, so that the sliding portion moves upward along the sliding slot. 
     
     
       20. The keyswitch of  claim 19 , wherein the sliding portion has an upper edge, the base has an accommodating space and a lower surface corresponding to the upper edge, the protruding portion is higher than the upper edge and received within the accommodating space, the upper edge is beneath the lower surface, so that the sliding portion moves upward along the sliding slot until the upper edge engaging with the lower surface of the base. 
     
     
       21. A keyswitch, comprising:
 a base, the base comprising an accommodating space, a lower surface, a first sliding part, and an elastic piece socket, the elastic piece socket comprising a sliding slot; 
 a keycap, the keycap comprising an engaging part and a second sliding part, the first sliding part and the second sliding part being slidably engaged with each other, so that a movement of the keycap between an initial position and a transition position is a linear movement; 
 a spring, disposed between the keycap and the base, so that when the keycap receives a pressing force to move from the initial position toward the base, the keycap transfers the pressing force to the spring; and 
 an elastic piece, the elastic piece comprising a sliding portion, a protruding portion, and an elastic portion, the elastic portion being formed between the protruding portion and the sliding portion, the sliding portion having an upper edge; 
 
       wherein the protruding portion is higher than the upper edge, the protruding portion is located within the accommodating space, and the lower surface is right above the upper edge; 
       wherein the elastic piece is slidably disposed in the elastic piece socket by the sliding portion sliding in the sliding slot; 
       wherein when the keycap moves downward toward the base, the engaging part obliquely upward pushes against the protruding portion to make the protruding portion move freely within the accommodating space, so that the sliding portion moves upward until the upper edge engaging with the lower surface of the base.